I have a french door refrigerator model LRFWS2906S went to replace the air filter that is behind the panel at the top back the unit but there is no air filter.  On visual inspection there is no fan that I can behind this panel, only styrofoam.  Not sure how the unit can provide multi flow air filtration without a fan unit in this chamber.  We occassionally get an odor from the fridge which we have confirmed is not from bad food.